SOLUTION: You have two lazy friends that offer to help paint your house. You can paint the house in 10 hours jeff can paint it in 12 and andy can paint it in 18. You work the entire time but

Algebra ->  Rate-of-work-word-problems -> SOLUTION: You have two lazy friends that offer to help paint your house. You can paint the house in 10 hours jeff can paint it in 12 and andy can paint it in 18. You work the entire time but      Log On


   

Question 1094895: You have two lazy friends that offer to help paint your house. You can paint the house in 10 hours jeff can paint it in 12 and andy can paint it in 18. You work the entire time but Jeff ended up taking an hour break and Andy took a 2-hour break. If you started painting at 8 am what time did you finish?
Thanks for helping!
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
You can paint the house in 10 hours
jeff can paint it in 12 and
andy can paint it in 18.
You work the entire time but Jeff ended up taking an hour break and Andy took a 2-hour break.
If you started painting at 8 am what time did you finish?
:
let t = no. of hrs from 8 Am to complete the job
then
(t-1) = painting time of Jeff
and
(t-2) = painting time of Andy
:
let the completed job = 1
:
Each will do a fraction of the job, the 3 fractions add up to 1
t%2F10 + %28%28t-1%29%29%2F12 + %28%28t-2%29%29%2F18 = 1
multiply by the least common multiple 180, then cancel the denominators
18t + 15(t-1) + 10(t-2) = 180
18t + 15t - 15 + 10t - 20 = 180
18t + 15t + 10t = 180 + 15 + 20
43t = 215
t = 215/43
t = 5 hrs, 8:00 + 5:00 = 13:00 or 1 pm they finish